Ranger Electronic Communications Inc SM-099 Manuale Utente

 

 

- 4 -

 

INSTALLATION 

                                                                                                                                                                                                                                                                                                                                                                                                   

A                                                                             

Use of a mobile receiver at low signal levels is normally limited by the presence of electrical 

noise. The primary source of noise in automobile installation is from the generator and ignition 
system in the vehicle. Under most operating conditions, when signal level is adequate, the 
background noise does not present a serious problem. Also, when extremely low level signals 
are being received, the  transceiver may be operated with vehicles engine turned off. The unit 
requires very little current and therefore will not significantly discharge the vehicle battery. 

 
Even though the transceiver has ANL and NB controls, in some installation ignition 

interference may be high enough to make good communications impossible. The electrical 

noise may come from several sources. Many possibilities exist, as variations between vehicles 
require different solutions to reduce the noise. 
 

A vertically polarized, quarter-wavelength whip antenna provides the most reliable operation 

and greatest range. Shorter, loaded-type whip antennas are more attractive, compact and 
adequate for applications where the maximum possible distance is not required. Also, loaded 
whips do not present the problems of high wind resistant imposed by a full quarter-wavelength 
whip.  

 
Mobile whip antennas utilize the metal body of the vehicle as a ground plane. When mounted 

at a corner of the vehicle they are slightly directional, in the direction of the body of the vehicle. 
For all practical purpose, however, the radiation pattern is nondirectional. The slight directional 

characteristic will be observed only at extreme distances. A standard antenna connector (type 
SO-239) is provided on the  transceiver for easy connection to a standard PL-259 cable 
termination. 

 

If the transceiver is not mounted on a metal surface, it is necessary to run a separate ground 

wire from the unit to good metal electrical ground in the vehicle. When installed in a boat, the 
transceiver will not operate at maximum efficiency without a ground plate, unless the vessel has 
a steel hull. 

 

Before installing the transceiver in a boat, consult your dealer for information regarding an 

adequate grounding system and prevention of electrolysis between fittings in the hull and water.    

    

 

 

 

- 5 -

 

INSTALLATION 

                                                                                                                                                                                                                                                                                                                                                                                                   

A                                             

Since there is such a wide variety of a base and mobile antenna, this section will strictly 

concern itself to the various types of mobile adjustable antennas.  

Because the antenna length is directly related to the channel frequency, it must be tuned to 

resonate optimally on all channels of the transceiver. Channel 1 requires a longer antenna than 
Channel 40 because it is lower in its frequency of operation. 

 Due to the various methods of adjusting antennas for proper S.W.R. we have chosen what 

we think is the optimum method: 

 

1.  Starts with the antenna extended and tighten the set screw lightly enough so that the 

antenna can be lightly tapped with your finger for easy adjustment. 

 
2.  Set your transceiver to Channel 20. Press the PTT (push-to-talk) switch, and tap the 

antenna (making it shorter). The S.W.R meter will show a lower reading each time the 
antenna is tapped. By continuing to shorten the antenna, you will notice the S.W.R reading 
will reach a low point and then start rising again. This means that you have passed the 
optimum point for Channel 20. 

 

Extend the antenna a short distance and again follow the procedure above. When the lowest 

point  has been reached, switch to Channel 1 and then to Channel 40 and compare S.W.R 
readings. They should be almost equal. 
 

 

 

1.  Follow the same procedure as above but adjust the length by cutting in 1/8” increments 

until a good match is obtained. 

 
2.  Be very careful not to cut too much at one time, as one it is cut, it can no longer be 

 
3.  The whip is easily cut by filing a notch all the way around and breaking the piece off with 

pliers.